Rhegmatogenous Retinal Detachment after Molteno Glaucoma Implant Surgery

Rhegmatogenous Retinal Detachment after Molteno Glaucoma Implant Surgery William ]. Waterhouse, MD, Mary Ann E. Lloyd, MD, Pravin U. Dugel, MD, Dale K. Heuer, MD, George Baerveldt, MD, Don S. Minckler, MD, Peter E. Liggett, MD Background: The Molteno implant is a device used for surgical treatment of complicated glaucoma. Rhegmatogenous retinal detachment (RD) is a relatively rare complication of Molteno implant surgery. This study was undertaken to evaluate the clinical features including the surgical management and postoperative outcome of patients with rhegmatogenous RD after Molteno implant surgery. Methods: The authors reviewed 350 consecutive patients who had Molteno surgery and identified 16 patients with subsequent rhegmatogenous RD. They also studied one patient referred for RD repair after Molteno surgery at another institution. Results: The risk of rhegmatogenous RD was 5%. Seventy percent (12/17) of the patients presented within 4 months of the Molteno procedure. Dialysis and flap tear were the most common types of retinal break found. Forty-one percent (7/17) of the patients had proliferative vitreoretinopathy. In three patients, clinical features suggested RD resulting from the Molteno procedure. In other patients, previous ocular surgery and underlying ocular disease may have contributed to the development of RD. Retinal detachment repair was attempted in all patients. Among 16 patients with at least 6 months of follow-up, 56% (9/16) had successful retina attachment. Forty-four percent (7/16) of the patients maintained formed vision. Eighteen percent (3/16) of the patients maintained visual acuity of at least 20/40. Intractable glaucoma did not develop in any of the patients with an attached retina. Recurrent RD, endophthalmitis, cyclitic membrane, or intractable glaucoma led to phthiSis bulbi or enucleation in 44% (7/16) of the patients. Conclusion: A combined approach by vitreoretinal and glaucoma surgeons can restore vision and maintain glaucoma control in patients with rhegmatogenous RD associated with Molteno implant surgery. Ophthalmology 1994;101:665-671

Originally received: May 12, 1993. Revision accepted: October 8, 1993. From the Department of Ophthalmology, University of Southern California School of Medicine and the Doheny Eye Institute, Los Angeles. Presented in part at the ARVO, Sarasota, May 1993. Dr. Waterhouse is now with the Ophthalmology Service, Fitzsimons Army Medical Center, Aurora, Colorado. Dr. Lloyd is now with the Ophthalmology Department, Palo Alto Medical Foundation, Palo Alto. Dr. Liggett is now with the Department of Ophthalmology, Yale School of Medicine, New Haven.

Molteno implants are useful in the surgical treatment of complicated glaucoma. The Molteno implant provides aqueous drainage from the anterior or posterior chamber via an implanted tube to a reservoir sutured to the episclera at the equator of the gloce. The diverted aqueous diffuses across the surrounding capsule and is absorbed Dr. Dugel is the recipient of the 1992-1993 Heed Foundation Fellowship Award and the Ronald G. Michels Vitreoretinal Surgery Fellowship Award.

The authors have no financial interest in Molteno implants.

The views expressed are those of the authors and do not necessarily reflect the views of the United States Army, the Department of Defense, or the United States Government.

Dr. Baerveldt has a financial interest in another glaucoma implant manufactured by another company.

Reprint requests to William J. Waterhouse, MD, Ophthalmology SVC, HSHG-SGH, Fitzsimons AMC, Aurora, CO 80045-5001.

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by capillaries or lymphatics in periocular tissu.es. Indications for its use include patients who have faIled conventional filtering surgery or who have a poor prognosis such as neovascular glaucoma, infantile glaucoma, and aphakic glaucoma. Complications of surgery with the Molteno implant include hypotony, hemorrhage, extrusion infection cataract, corneal decompensation, diplo" • 1 pia, and failure to control the mtraocular press~re. Rhegmatogenous retinal detachment (RD) is a relatIvely rare complication of Molteno implant surgery (Figs 1 and 2). We retrospectively reviewed our experience treating patients with rhegmatogenous RD after Molteno implant surgery to evaluate the causes of RD and the outcomes of RD repair.

Subjects and Methods We reviewed the records of the Estelle Doheny Eye Hospital and Los Angeles County Hospital from 1985 to 1991 and identified 18 patients with rhegmatogenous RD in eyes that previously had undergone Molteno implant surgery. Among 350 consecutive patients, rhegmatogenous RD developed in 16. Two patients were referred for repair of RD after Molteno surgery was done at another institution. One of these was excluded from study because the first RD operation was done before referral to our hospital. Patients with traction RD without retinal holes and those in whom RD was present before Molteno implant surgery were excluded. The records of the remaining 17 patients were analyzed with attention to patient age, race, and sex, type of glaucoma, prior ocular surgery, factors related to the Molteno surgery, status of the lens, extent of the RD, location of retinal holes, and presence of proliferative vitreoretinopathy (PVR). We reviewed the surgical techniques used to reattach the retina, including management of the Molteno implant. The surgical success was determined by studying visual outcome, retinal position, intraocular pressure, and complications.

Figure 1. Eye with Molteno implant and rhegmatogenous retinal detachment. The detached retina is visible through the pupil, behind the Molteno tube.

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Figure 2. B-scan ultrasound demonstrates rhegmatogenous retinal detachment (r). The Molteno implant (m) is surrounded by aqueous fluid, lying over flattened sclera (s).

Results Seventeen patients were identified who had had rhegmatogenous RD after Molteno glaucoma implant surgery. Sixteen of these were among 350 consecutive patients who had had Molteno surgery at the Doheny Eye Institute, yielding an estimated 5% (16/350) risk ofrhegmatogenous RD after Molteno surgery. One patient was referred for treatment of RD after having had Molteno implant surgery elsewhere. Patient data are summarized in Table 1. The patients ranged in age from 5 months to 82 years (median, 9 years). There were nine males and eight females. The most common glaucoma diagnoses were infantile glaucoma and glaucoma after removal of congenital cataract. The number of intraocular operations before RD ranged from two to six (median, 3). In 12 patients, the most recent intraocular procedure was a one-stage Molteno implantation or the second stage of a two-stage Molteno implant. In two patients, the most recent procedure was a pars plana vitrectomy. Two patients' RDs were preceded by penetrating keratoplasty with anterior vitrectomy. One patient had had a Molteno implant tube ligature release before RD. Seventy percent (12/17) of the patients had RD within 4 months of their last Molteno procedure, and 29% (5/17) within 1 month. Fifteen patients were aphakic, one was pseudophakic, and one was phakic. Retinal dialysis and flap (horseshoe) tears were the types of retinal break found most often at the time of detachment repair. Each was found in four eyes. Two eyes had giant tears, two had round holes, and one had a tear associated with lattice degeneration. The type of retinal tear was not described in the records of two patients. The causative retinal tear was not identified in one case of total detachment with an anatomic configuration typical of rhegmatogenous RD complicated by PVR. On initial presentation, PVR was found in 41 % (7/17) of patients. The severity of PVR was graded using the Retina Society Classification. 2 One patient had C-l PVR,

Waterhouse et al . Rhegmatogenous Retinal Detachment Table 1. Data Summary (17 eyes of 17 patients) Age (yrs) Range Median Mean ± SD Sex M F Race White Hispanic Non-Hispanic Black Asian Type of Glaucoma Infantile glaucoma Pediatric glaucoma after congenital cataract surgery Aphakic open angle glaucoma Glaucoma after penetrating trauma Glaucoma after blunt trauma Angle closure glaucoma with nanophthalmos Glaucoma associated with Peter's Anomaly Open angle with uveitis Lens Status Aphakic Pseudophakic Phakic No. of Prior Intraocular Operations Range Mean ± SD Interval from Last Molteno Operation to Detachment (mos) Range Mean ± SD

Type of Retinal Hole Dialysis 5/12-82 Flap tear 9 23.9 ± 25.8 Giant tear Round hole 9 (53%) Break with lattice degeneration Not specified 8 (47%) Not identified 15 (88%) 6 (35%) 9 (53%) 1 (6%) 1 (6%) 4(24%) 4 (24%) 3 (18%) 2 (12%) 1 (6%) 1 (6%) 1 (6%) 1 (6%) 15 (88%) 1 (6%) 1 (6%)

4 (24%) 4 (24%) 2 (12%) 2 (12%) 1 (6%) 3 (18%) 1 (6%)

Proliferative Vitreoretinopathy· Absent Present C-l D-l D-2 D-3 Anterior loop traction

10 (59%) 7 (41%) 1 (6%) 2 (12%) 2 (12%) 1 (6%) 1 (6%)

Technique of Retinal Detachment Repair Scleral buckle with gas tamponade Pars plana vitrectomy with gas tamponade With scleral buckle Without scleral buckle Pars plana vitrectomy with silicone oil tamponade With scleral buckle Without scleral buckle

1 (6%) 11 (65%) 6 (35%) 5 (29%) 5 (29%) 4 (24%) 1 (6%)

Managment of Molteno Implants during Retinal Detachment Repair Molteno not changed Molteno tube ligated 2-6 Molteno tube removed, plate undisturbed 3.8 ± 1.2 Molteno implant replaced Stage 1 Molteno implant placed Stage 1 and complete (one-stage) Molteno implants placed 0.5-66 Schocket implant placed 9.3 ± 16.2 Duration of Follow-up (mos) Range Mean ± SD

10 (58%) 2 (12%) 2 (12%) 3 (18%) 1 (6%) 1 (6%) 1 (6%) 4-48 20.4 ± 15.8

SD = standard deviation. 'C-l = fixed retina folds in one quadrant; D-l = fixed retina folds on each quadrant, open funnel retina configuration; D-2 = narrow funnel retina configuration; D-3 = closed funnel retina configuration.

two had D-I PVR, two had D-2 PVR, and one had D-3 PVR. Anterior loop traction, with retina adherent to iris, was present in another patient. Surgery to reattach the retina was attempted in each patient. One patient was treated with an encircling scleral buckle and intravitreal gas injection, without pars plana vitrectomy. All other patients had pars plana vitrectomy and intraocular tamponade, using either gas or silicone oil. Pars plana lensectomy was done during vitrectomy for one patient because cataract obscured the retina. A three-port pars plana vitrectomy was performed. Small conjunctival peritomies were used for the exposure of

sclera for the sclerotomies. When possible, the Molteno tubes were avoided when making sclerotomies. Epiretinal membranes were removed in patients with PVR. Subretinal fluid was drained through a drainage retinotomy if fluid could not be removed through a pre-existing retinal break. During internal drainage of subretinal fluid, the retina was reattached by air-fluid exchange. Laser photocoagulation or cryopexy was used to surround all retinal tears, followed by infusion of long-acting gas or silicone oil. Sulfurhexafluoride gas was used in five patients. Perfluoropropane gas was used in six patients. Silicone oil was used in five patients. An encircling scleral buckle was

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Figure 3. An eye during pars plana vitrectomy, scleral buckle surgery, and Molteno implant modification. The Molteno tube has been removed from inside the globe and tucked under a rectus muscle. An encircling band has been placed between the scleral graft and the Molteno plate.

used in ten of the patients who had had vitrectomy. In those patients with a scleral buckle, a 360 0 conjunctival peritomy was made. The scleral buckles were placed anterior or over functioning Molteno plates; nonfunctioning Molteno plates were removed, and replacement plates were positioned over the buckle (Figs 3 and 4). The Molteno implants were left unchanged at the time ofRD repair in ten patients. The Molteno tubes were ligated with absorbable suture in two patients. In two patients, functioning Molteno implant tubes were repositioned from inside the globe to the scleral surface behind the rectus muscle insertions for possible reinsertion at a later date. The Molteno implants were removed in three patients, replaced with a new stage 1 Molteno implant in one patient, a Schocket implant in the second patient, and both a stage I Molteno implant and a complete (1-stage) Molteno implant in the third patient. Meticulous conjunctiva closure concluded each operation, with care to cover each sclerotomy, Molteno implant, and scleral buckle. Postoperatively, patients were treated with topical steroids, antibiotics, and cycloplegics. The duration of follow-up after RD repair ranged from 4 to 48 months. At least 6 months offollow-up was available for 94% (16/17) of the patients. The findings of their most recent examinations are summarized in Table 2. The retina was attached in 56% (9/16) of patients. Seventyeight percent (7/9) of the patients with attached retinas maintained formed vision, defined as best-corrected visual acuity of at least 1/200, or counting fingers. Three patients had a visual acuity of at least 20/40. One patient had a visual acuity of20/ 100. Three patients had a visual acuity in the counting-fingers range. Table 3 lists the visual acuities before detachment, with detachment, and final visual acuities. Two of these patients only had counting fingers or a visual acuity of less than 20/400 before their retinas detached. A patient with an attached retina but only hand motions visual acuity had a dense retrocomeal membrane due to fibrous downgrowth. One patient required three

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Figure 4. An eye during pars plana vitrectomy, scleral buckle surgery, and Molteno implant surgery. A double-plate Molteno implant has been sutured to the 7-mm encircling scleral buckle. The Molteno tube is tucked under the buckle for future use.

retina operations because of recurrent detachment. Although his retina finally was attached, the visual result was no light perception. The final intraocular pressure was less than 22 mmHg for all patients whose retinas remained attached. One of these patients had hypotony. Antiglaucoma medications were used when necessary after RD repair. No additional glaucoma operations were needed for 89% (8/9) of the patients whose retinas were attached at last examination. One of these patients required a Schocket operation to maintain pressure control.

Table 2. Outcome after Retinal Detachment Surgery (16 eyes of 16 patients with more than 6 months of follow-up) Retina Attached Visual acuity

9 (56%)

20/ 30 20/ 40 20/100 3/ 200 1/ 200

1 (6%) 2 (13%) 1 (6%) 1 (6%) 1 (6%) 1 (6%) 1 (6%) 1 (6%)

CF at 1 ft

HM

NLP Intraocular pressure (mmHg) >5 and <22

8 (50%) 1 (6%)

<5

Retina Detached Final globe status Phthisis bulbi Recurrent detachment Endophthalmitis Cyclitic membrane Enucleated for intractable glaucoma CF

=

counting fingers; HM

=

hand motions; NLP

7 (44%) 6 (38%) 3 (19%) 2 (13%) 1 (6%) 1 (6%) =

no light perception.

Waterhouse et al . Rhegmatogenous Retinal Detachment Table 3. Visual Acuity Data of Patients with Retinas Attached at Last Examination Visual Acuity Case No.

Before RD

With RD

Final

1 2 3 4

20/40 20/40 20/100 Unknown CF

HM CF 20/40 20/100 HM

20/30 20/40 20/40 20/100 3/200

HM CF HM

1/200 CF at 1ft HM

20/100

NLP

5 6

7

20/80 CF

8

1/200

9

20/100

Comment RD involved macula RD involved macula RD involved macula, band keratopathy RD involved macula Corneal edema RD involved macula, fibrous ingrowth Recurrent RD requiring 3 operations

RD = retinal detachment; HM = hand motions; CF = counting fingers; NLP = no light perception.

In 44% (7/16) of the patients, the retina was detached at the last examination. Phthisis bulbi developed in 38% (6/16) of these patients. The most common cause of phthisis bulbi was recurrent RD, which occurred in three patients. Two of these patients had recurrent rhegmatogenous RD. Two additional attempts to reattach the retina were unsuccessful on one patient who had recurrent PVR. The second patient did not have additional surgery. A traction RD developed in the third patient after removal of silicone oil, and this patient did not have additional surgery because of the degree of optic nerve pallor. Phthisis bulbi developed in two patients due to infectious endophthalmitis caused by Streptococcus pneumoniae. One patient received a diagnosis 3 days after RD repair. Infectious endophthalmitis developed in the other patient 2 weeks after adjustment of a Schocket tube, 4 months after retinal surgery. Both eyes were lost, despite treatment with intravitreal vancomycin, gentamicin, and dexamethasone. Phthisis bulbi developed in one patient because of a cyclitic membrane that developed 3 weeks after RD surgery. Intractable glaucoma with recurrent RD developed in one patient, who underwent enucleation for a blind and painful eye.

Selected Case Reports Case 1. A 9-year-old white girl had a history of prior lensectomy at the time of repair of a penetrating injury to her left eye. Two filtration operations for secondary glaucoma were unsuccessful. A one-stage Molteno implant was done, which controlled her glaucoma, but after 6 months the tube retracted out of the anterior chamber. The Molteno implant was removed, and a new one was placed, but the intraocular pressure remained

high. A new one-stage Molteno implant was placed in another quadrant, with the tube also in the anterior chamber. A 5-0 collagen suture was used to ligate the tube of the new implant. The visual acuity was 20/400. Three months later, the ligature was released. Hemorrhagic choroidal detachments with retinal apposition ("kissing choroidals") immediately developed in the eye. As the choroidal detachments resolved, there was RD. The visual acuity was light perception. Retinal reattachment was accomplished by pars plana vitrectomy, scleral buckle, and silicone oil tamponade of the large peripheral retinal tear. Proliferative vitreoretinopathy was present in the form of anterior loop traction. Residual suprachoroidal hemorrhage was drained through sclerotomies. The scleral buckle was a 2.5-mm encircling band placed anterior to the Molteno plates, under the tubes. The Molteno tubes were ligated. Two months after retinal surgery, the vision declined to no light perception, and the retina redetached due to retinal membrane proliferation. Four years later, intractable glaucoma developed and the blind, painful eye was enucleated. Case 2. A 29-year-old white woman with nanophthalmos was referred for treatment of a~ RD in her left eye. Previously, an episode of acute angle-closure glaucoma was treated with an anterior vitrectomy. Because of persistent glaucoma, pars plana lensectomy and Molteno implant were done. Three months later, the Molteno implant was revised. Visual acuity was 20/40. Four months later, the patient noted central blur and loss of the nasal visual field in the left eye. Results of examination showed a rhegmatogenous RD involving the macula, with visual acuity of counting fingers. A Molteno implant was present in the superotemporal quadrant with its tube in the posterior chamber through the pars plana. The eye was aphakic. The intraocular pressure was 8 mmHg. Vitreous gel occluded the Molteno tube, and a flap tear of the retina was in the same meridian as the tube. The retina was reattached by pars plana vitrectomy, using sulfurhexafluoride gas for internal tamponade. Ten months later, visual acuity was 20/40. The intraocular pressure was 16 mmHg, without the use of glaucoma medications. Case 3. A 12-year-old white boy had uncontrolled secondary glaucoma related to penetrating trauma to the right eye with a fork at 11/2 years of age. Cataract extraction and anterior intraocular lens insertion had been done at 10 years of age. Visual acuity was 20/200. An unsuccessful trabeculectomy was done. One month later, the intraocular lens was removed, an anterior vitrectomy was done with removal of a pupillary membrane, and the first stage ofa two-stage Molteno glaucoma implant was placed. While suturing the Molteno plate to the globe, a needle inadvertently perforated the sclera in the superotemporal quadrant, with release of liquid vitreous. Transscleral cryopexy was applied at the perforation site. The second stage of the Molteno operation was done 1 month after the stage 1 procedure. The tube was placed in the anterior chamber via a superotemporal limbus incision. Retinal detachment was noted 1 month later. Visual acuity was 2/200. Because of his scarred cornea, vitrectomy was done using a temporary keratoprosthesis with penetrating keratoplasty. A giant retinal tear was present from the 6- to 10o'clock meridians, producing a total RD. The Molteno implant tube was removed and tucked under the plate as in a stage I procedure. A scleral buckle was placed with a 7-mm circumferential silicone explant supporting the giant tear and a 2.5-mm band encircling the globe. A new stage 1 Molteno implant was placed over the buckle, behind the band, in the inferotemporal quadrant. Silicone oil was used for internal tamponade. The oil was removed 11 days later, and the second stage ofthe Molteno implant was done. The retina remained attached and the pressure controlled. One year later, visual

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acuity was counting fingers at I foot due to a fibrotic band across the macula. Vision gradually declined to hand motions due to traction RD caused by subretinal membranes. The intraocular pressure remained in the mid-teens. No further RD surgery was done because the disc was extremely pale. Phthisis bulbi resulted.

Discussion In this study, we retrospectively reviewed patients with rhegmatogenous RD after Molteno implant surgery at our institution to gain insight into the risk of detachment, the clinical features of those patients, possible mechanisms for retinal hole formation, and the results of treatment. Some of the patients in this study were included in the data from previous reports of Molteno implant surgery from our institution. 3-6 Another study reported one case of rhegmatogenous RD among 23 eyes of 18 patients with developmental glaucoma who had two-stage implantation of the doubleplate Molteno device. 7 The detachment occurred 3 years after surgery, and the break was unrelated to the Molteno implant. Other investigators have described RD after Molteno implant surgery, but their detachments were due to traction without retinal breaks,8-10 or they do not describe whether the patients had rhegmatogenous or tractional RDs.1.l 1- 13 Three hundred fifty patients underwent Molteno implant surgery at the Doheny Eye Institute during the time of this study. Sixteen of the 17 patients in this study had their Molteno operation at the Doheny Eye Institute, allowing an estimated postoperative risk ofrhegmatogenous RD of 5% (16/350). In this series, no single mechanism accounted for retinal hole formation leading to RD. Prior surgery other than Molteno surgery probably played a role in the pathogenesis of RD in some of these patients. In two patients, the operation preceding RD was pars plana vitrectomy. Retinal detachment is a known complication of pars plana vitrectomy.14 Two patients had penetrating keratoplasty with anterior vitrectomy as the most recent surgery before RD occurred, suggesting that the Molteno operation did not cause detachment in those patients. Posterior vitreous detachment is the likely cause of retinal tear formation in some of the patients. One patient had lattice degeneration and another had chorioretinal scars associated with old uveitis. These types of abnormal vitreous adhesion to the retina led to the development of retinal holes with posterior vitreous separation. Underlying ocular disease, such as ocular trauma or uveitis, and the high number of prior intraocular procedures, likely played a role in vitreous syneresis and posterior vitreous detachment. All except 1 of the 17 patients had aphakia or pseudophakia, another factor predisposing posterior vitreous detachment and subsequent RD. In a few patients, the mechanism of RD strongly was suggested by the history of prior surgery, the type and location of retinal breaks, or the time course of RD with respect to previous operations. An example of this is case

670

I, in whom RD occurred as a consequence of retinal apposition due to hemorrhagic choroidal detachment after releasing the ligature on the Molteno tube. The hemorrhagic choroidal detachments occurred immediately upon opening the Molteno tube, and the RD that followed certainly was related to retinal apposition from the "kissing choroidals." In that patient, RD was a direct result of the Molteno operation. Case 2 suggests another mechanism of rhegmatogenous RD after Molteno surgery. There was a flap tear in the same meridian as vitreous incarceration into the Molteno implant tube. Although vitreous incarceration into the tube may have been the mechanism for flap tear formation, the two also may have been unrelated. This occurred in an eye with nanophthalmos. Anterior displacement of vitreous after lensectomy is more common in eyes with nanophthalmos, typically producing malignant glaucoma. The incarceration of vitreous in the tube may have occurred after RD. Case 3 illustrates the difficulty of determining the cause of RD in an eye with severe underlying disease and multiple previous operations. The RD may have been related to an inadvertent scleral perforation during Molteno placement. The perforation was recognized and treated immediately with cryopexy, but detachment occurred with a single retinal break in the same quadrant as the perforation. At the time of repair, there was no evidence of ocular perforation or linear chorioretinal scars, but the cryopexy may have obscured those features of the perforation. It is not clear from the operation report whether the tear found at repair was associated with the cryopexy scar. Alternatively, the tear may be attributed to the anterior vitrectomy which was done at the time of the stage 1 Molteno surgery. A third possibility is that the tear was related to the original trauma. This possibility is based on the association of giant retinal tears with previous ocular trauma. A role for iatrogenic retinal tears also is suggested by the presence of retinal dialysis in three patients. In one of these patients, the dialysis was in the same quadrant as a pars plana-positioned Molteno implant tube. A dialysis could be created during the needle pass while creating the pars plana sclerotomy for the Molteno tube or during the tube insertion. In the two other patients, retinal dialysis may have occurred during previous lens extraction with anterior vitrectomy, unrelated to Molteno surgery. Proliferative vitreoretinopathy was present in 41 % (7/ 17) of the patients in this series. This high rate of PVR likely is related to the large number of previous operations in these eyes. Such eyes typically have chronic inflammation which predisposes to membrane formation in association with rhegmatogenous RD. 15 Proliferative vitreoretinopathy also has reportedly occurred in 60% (3/5) of a consecutive series of RD in eyes with infantile glaucoma. 16 Of the cases ofPVR in our series, 43% (3/7) were patients with infantile glaucoma. Because of the high prevalence of PVR and the desire to minimize disturbing, functioning Molteno plates, our surgical approach for repairing the RDs involved pars plana vitrectomy in 94% (16/17) of the patients. A team

Waterhouse et al . Rhegmatogenous Retinal Detachment approach was used involving both the Glaucoma Service and the Retina Service. The team approach allowed coordinated attention to the maintenance or restoration of functioning Molteno plates along with the goal of retinal reattachment. Fifty-six percent (9/16) of patients with at least 6 months of follow-up had attached retinas. Each of these eyes maintained intraocular pressure control, but one was hypotonus, and one required additional glaucoma surgery. Three patients had a final visual acuity of 20/40 or better. F orty-four percent (7/16) of the patients had formed visual acuity of at least counting fingers at the most recent examination. Causes oflimited visual acuity included glaucomatous optic atrophy, macular involvement by the RD, fibrous downgrowth, corneal edema, and band keratopathy. The remaining 44% (7/16) of patients with phthisis or enucleation emphasize the guarded prognosis for globes in which rhegmatogenous RD develops after Molteno implant surgery. The most common cause of phthisis or enucleation was recurrent RD. Two eyes were lost due to bacterial endophthalmitis. In one of these eyes, bacterial endophthalmitis occurred within 3 days of the retinal repair and most likely was due to intraoperative contamination. Bacterial endophthalmitis developed in the other patient 2 weeks after revision of a Schocket tube (4 months after retina repair). The tendency for glaucoma hardware to erode through conjunctiva has been reported as a cause of infectious endophthalmitis after seton implantation. 17 We carefully covered all implanted Molteno tubes with donor sclera grafts and performed meticulous conjunctiva closure to minimize the risk of exposure and infection. One globe was lost to cyclitic membrane formation, before the advent of intraocular tissue plasminogen activator treatment of fibrin membranes. In subsequent cases, the use of tissue plasminogen activator to dissolve intraocular fibrin prevented the development of cyclitic membranes.

References I. Melamed S, Fiore PM. Molteno implant surgery in refractory glaucoma. Surv Ophthalmol 1990;34:441-8.

2. The Retina Society Terminology Committee. The classification of retinal detachment with proliferative vitreoretinopathy. Ophthalmology 1983;90:121-5. 3. Minckler DS, Heuer DK, Hasty B, et al. Clinical experience with the single-plate Molteno implant in complicated glaucomas. Ophthalmology 1988;95:1181-8. 4. Hill RA, Heuer DK, Baerveldt G, et al. Molteno implantation for glaucoma in young patients. Ophthalmology 1991 ;98: 1042-6. 5. Lloyd MA, Heuer DK, Baerveldt G, et al. Combined Molteno implantation and pars plana vitrectomy for neovascular glaucomas. Ophthalmology 1991 ;98: 1401-5. 6. Lloyd MA, Sedlak T, Heuer DK, et al. Clinical experience with the single-plate Molteno implant in complicated glaucomas. Update of a pilot study. Ophthalmology 1992;99: 679-87. 7. Billson F, Thomas R, Aylward W. The use of two-stage Molteno implants in developmental glaucoma. J Pediatr Ophthalmol Strabismus 1989;26:3-8. 8. Traverso CE, Tomey KF, Al-Kaff A. The long-tube single plate Molteno implant for the treatment of recalcitrant glaucoma. Int Ophthalmol 1989; 13: 159-62. 9. Huna R, Melamed S, Hirsh A, Treister G. Retinal detachment adherent to posterior chamber IOL after Molteno implant surgery. Ophthalmic Surg 1990;21 :854-6. 10. Melamed S, Cahane M, Gutman I, Blumenthal M. Postoperative complications after Molteno implant surgery. Am J Ophthalmol 1991;111:319-22. II. Downes RN, Flanagan DW, Jordan K, Burton RL. The Molteno implant in intractable glaucoma. Eye 1988;2:250-9. 12. Beebe WE, Starita RJ, Fellman RL, et al. The use of Molteno implant and anterior chamber tube shunt to encircling band for the treatment of glaucoma in keratoplasty patients. Ophthalmology 1990;97:1414-22. 13. Munoz M, Tomey KF, Traverso C, et al. Clinical experience with the Molteno implant in advanced infantile glaucoma. J Pediatr Ophthalmol Strabismus 1991 ;28:68-72. 14. Carter JB, Michels RG, Glaser BM, De Bustros S. Iatrogenic retinal breaks complicating pars plana vitrectomy. Ophthalmology 1990;97:848-54. 15. Ryan SJ. The pathophysiology of proliferative vitreoretinopathy in its management. Am J Ophthalmol 1985;100: 188-93. 16. Wiedemann P, Heimann K. Retinal detachment in eyes with congenital glaucoma. Retina 1992; 12(Suppl):S51-4. 17. Krebs DB, Liebmann JM, Ritch R, et al. Late infectious endophthalmitis from exposed glaucoma setons. Arch Ophthalmology 1992; 110: 174-5.

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